chain to base Grx.Application event handler

this handls APP_* events and ignores all other events when is_active == false

src/ConsoleApp.vala

@@ -74,11 +74,14 @@ namespace Ev3devKit {
         }
 
         public override bool event (Grx.Event event) {
+            if (base.event (event)) {
+                return true;
+            }
             if (event.type == Grx.EventType.KEY_DOWN) {
                 Ui.Screen.active_screen.queue_key_code (event.key.keysym);
                 return true;
             }
             return false;
         }
     }
-}
+}